Massive fatal overdose of abrin with progressive encephalopathy.

Introduction: The jequirity bean (Abrus precatorius) seed contains abrin, a toxalbumin, that irreversibly binds the 60-s ribosomal subunit inhibiting protein synthesis. Neurologic manifestations of ingestions are rare.Case details: We present a case of a 20-year-old man with 24 h of vomiting, diarrhea and 2 h of hematemesis and hematochezia. He admitted to purchasing 1000 jequirity beans online, crushing and ingesting them 26 h prior to presentation in a suicide attempt. Over the next 2 days, he developed hallucinations, incomprehensible mumbling and grunting, disconjugate gaze with abnormal roving eye movements and a left gaze preference with his right eye deviated medially. There was a fine tremor of the upper extremities and he had brief episodes of choreoathetoid movements of his legs. A head CT was normal with no cerebral edema. He progressed to minimally responsive to noxious stimuli, and was unable to converse or follow commands and displayed increased choreoathetoid movements of his extremities. An electroencephalogram (EEG) showed only mild background slowing. Magnetic resonance imaging (MRI) was performed showing bilaterally symmetric signal abnormalities in the basal ganglia, brainstem, corpus callosum and corona radiata with diffuse leptomeningeal enhancement. The patient developed a tonic-clonic seizure followed by pulseless electrical activity, from which he was resuscitated. He was provided comfort care and died just under 5 days after his ingestion.Results: Urine analysis using liquid chromatography coupled to tandem mass spectrometry was positive for 8.84 ng/ml of l-abrine (4.96 ng l-abrine/mg creatinine) 61 h after admission to the hospital (approximately 87 h post-ingestion). Serum concentrations for l-abrine and ricinine were both below the limits of detection.Discussion: Ingestion of 1000 crushed jequirity beans purchased on the internet resulted in progressive encephalopathy and death.

Radioimmunoassays of abrin and ricin in blood.

Radioimmunoassays for abrin and ricin are described. There is little cross-reactivity between the two toxins. The procedures described are capable of determining blood concentrations down to 50-100 pg/ml, permitting identification of abrin and ricin poisoning and monitoring of the blood concentrations in cancer patients treated with these agents.

Kinetics of binding of the toxic lectins abrin and ricin to surface receptors of human cells.

Kinetic parameters of the interaction of the toxic lectins abrin and ricin with human erythrocytes and HeLa cells have been measured. The binding of 125I-labeled abrin and ricin to human erythrocytes and to HeLa cells at 37 degrees was maximal around pH 7, whereas at 0 degrees the binding was similar over a broad pH range. The binding occurred at similar rates at 0 degrees and 37 degrees with rate constants in the range 0.9 to 3.0 X 10(5) M-1 s-1. The dissociation was strongly temperature-dependent with rate constants in the range 3.4 to 45 X 10(-4) s-1 at 0 degrees and 3.9 to 18 X 10(-3) s-1 at 37 degrees. The presence of unlabeled lectins as well as lactose increased the rate of dissociation. The association constants measured at equilibrium or calculated from the rate constants were between 0.64 X 10(8) M-1 and 8.2 X 10(8) M-1 for abrus lectins, and between 8.0 X 10(6) M-1 and 4.2 X 10(8) M-1 for ricinus lectins. The association constants for the toxins were lower at 37 degrees than at 0 degrees. Isolated ricin B chain appeared to bind with similar affinity as intact ricin. The number of binding sites was estimated to be 2 to 3 X 10(6) per erythrocyte and 1 to 3 X 10(7) per HeLa cell. The binding sites of HeLa cells all displayed a uniform affinity towards abrin and ricin, both at 0 degrees and at 37 degrees. The same was the case with the binding sites of erythrocytes at 0 degrees. However, the data indicated that at 20 degrees erythrocytes possessed binding sites with two different affinities. Only a fraction of the cell-bound toxin appeared to be irreversibly bound and could not be removed by washing with 0.1 M lactose. The fraction of the total amount of bound toxin which became irreversibly bound to HeLa cells was for both toxins about 2 X 10(-3)/min at 37 degrees, whereas no toxin was irreversibly bound at 0 degrees. In the case of erythrocytes no toxin became irreversibly bound, either at 0 degrees or 37 degrees, indicating that the toxins are unable to penetrate into these cells.